Screening device



Patented Aug. 2 1926.

umrso STATES PATENT OFFICE.

CHARLES E. BARH IG-IZT, OF CARBONDALE, PENNSYLVANIA, ASSIGNOB TO CROSSEN- GINEERING COMPANY, A CORPORATION OF PENNSYLVANIA.

SCREENING DEVICE.

Application filed August 7, 1924. Serial No. 730,584.

My invention relates particularly to that class of screening or siftingdevices or machines in which material to be separated or graded isdelivered upon an inclined foram inous diaphragm or table, which ismechanically vibrated to so agitate said material that the fineparticles pass through the mesh of the screen while the coarse materialis caused to traverse the full length of said diaphragm or screen and bedischarged therefrom, and is especially directed to the mechanism bywhich said foraminous diaphragm is supported for agitation.

In vibrating screens it is desirable to pro vide strong vibrationof'considerable amplitude at the receiving or initial end of the screen,in order to properly agitate and move the heavy load of material asreceived, and to quickly carry the finer particles to the bottom of themass, so as to pass the mesh. It is also desirable to graduallyreducethe amplitude of vibration toward the discharge end of the screen so asto permit those particles of material that are just slightly smallerthan the mesh to pass through. If the entire screen were subjected tothe strong vibration required to treat the heavy mass of material at thereceiving end, the slightly under-sized parti cles would be caused totravel the length of the screen in a series of jumps which might preventtheir passing through the mesh except where they just happen to strike aperforation in such a way as to register therewith, but by reducing thevibration toward the discharge end so that these particles are just keptmoving without the jumping action, they may pass through to effect thedesired sizing.

Furthermore, in devices of the type contemplated wherein screens mountedupon coiled or spiral springs, or even upon springs of the leaf typetransversely disposed are vibrated, considerable longitudinal movementis produced which causes the vertical vibratory movement to have such alongitudinal component as to effect a compound vibration resolving intoan approximately circular or'oval movement of the it screen, which isnot only less effective than a direct perpendicular movement of saldscreen, but tends to be destructive both to the apparatus and to thebuilding in which it may be housed.

The principal objects of my invention are to provide a screen so mountedthat its vibratory action will be restricted to a motion perpendicularor normal to the plane of its screening surface, and when actuated thevibratory effect on said. screen will diminish gradually from itsinitial end to ward its discharge end.

Other objects of my invention are to provide a mounting for a screenupon which it may he so adjusted as to vary the relative amplitude ofvibration ofits initial and discharge ends. a

My invention comprehends a screen adjustably mounted for vibration uponspring supports which are extended in longitudinal relation withrespectto said screen, and includes means tending to relieve the weightof the screen on said spring supports.

Further objects of my invention are to embody in. a single unit aforaminous dia phragm and a subjacent imperforate pan, having means toso connect their plane effective surfaces as to vibrate in unison.

Specifically stated, the form of my inventionas hereinafter describedcomprises a base frame having longitudinally extended spring memberssupported adjacent to their ends and having an unbalanced rotary membermounted for rotation intermediate of the supports and a screen havingits frame supports spaced longitudinally on said spring members andarranged for longitudinal adjustment thereon into different spacedrelation to the supports of i said spring members,

My invention also includes all of the varr ous novel features ofconstruction and arrangement as hereinafter more definitely specified.

In the accompanying drawings, Figure 1 is a side elevational view of ascreening machine showing a convenient embodiment of my invention incooperative relation with a bin for discharging material therein; Fig. 2is a plan view of the screening structure illustrated in Fig. 1 ,asviewed in a direction normal to the plane of the screen surface,

and Fig. 3 is a transverse sectional view of the screening structureillustrated in Figs. 1 V

may be secured. together and to the stringers 1 to form the compositebase frame by the bolts 7 and 8 which also respectively er;- tendthrough the cross ties 2 and '3.

At the region substantially equidistant from their sup-ports Q'and 3-,the spring members5 are provided with the journals or bearings 9 inwhich the shaft 10 carrying a pair of eccentrics or out-of-balancewheels 11 having weights 12 is mounted for rotation by having its pulley13 connected by the belt 15 with the pulley 16 of the mo-' tor 17 whichis suitably disposed adjacent to the spring support 3.

.Superposed upon the spring members 5 and connected therewith forlongitudinal, adjustment is the screen frame whose standards QO-and 21rest upon the spring members 5 and may be secured in any desiredlongitudinal position thereon by the bolts 22 and 23 which extendupwardly through the longit-udinally directed slots 25 and 26 in saidspring members 5 and through the bores 27 and 28 in said standards,which bores intersect the transversely disposed apertures 29 and 30according convenient shoulders 31 and 32 upon which the nuts 33 and 34may impinge to rigidly secure said standards and spring members togetherin any desired longitudinal position.

The construction of the screen frame is not important in its precisedetails and may be widely varied. The typical illustration as shown inthe drawing comprises the perforated plate or foraminous diaphragm 35and the imperforate subjacent pan 36 arranged tocarry off the under sizematerial which is precipitated through said foraminous diaphragm, bothof which have their lateral margins clamped between the side timbers 39and 40 of the screen frame by the bolts 11.

The side timbers 39 and 40 are conveniently connected near their endsand central region by the transversely disposed angle irons 412 and atthe initial end of the screen by the cross beam l3 which also serves as'Said supporting the base frame comprising the stringers 1 upon one ofthe transversely dis posed brace bars serving to connect and brace theuprights or standards 51 of the bin 52 containing the material to besifted or screened which is delivered to. the screen by the extendedinclined floor'53 of said bin and controlled by the reciprocatory gate5%.

To insure the best results in the operation of the screen it isdesirable that the vibratory spring members 5 be relieved of the weightof the screen frame so as to permit the vibrating foraminous diaphragm35 to vibrate freely under heavy load. For this purpose the springs 55are provided, which may be connected at one end by the hooks 56 with thescreen frame as shown, and at the other end with the eye-bolts 57 whichare adjustably engaged with the brackets 58 suitably carried by thestandards 51 of the bin 52.

The constituents of the material separated by the screen may beconveniently directed to different containers by the chute 60 which isarranged to'receive the material discharged-from the foraminousdiaphragm 35 and the chute 61 onto which the material from the pan 36 isdischarged.

My invention is advantageous in that by the construction contemplatedthe vibration is so restricted as to be directly perpendicular to theplane of the screen surface, which motion has been found to be highlydesirable and far more effective and efficient than such devices asheretofore constructed where- 'in the vibration embodied a longitudinalcomponent. Furthermore, by so adjusting the screen frame that its rearstandards 21 are disposed on the spring members 5 relatively remote fromthe spring support 3 while the forward standardsQO are disposedrelatively close to the spring support 2, a greater vibratory action isnaturally effected upon the screen where the material is delivered'thereto, to wit, the initial or rearend thereof, and such vibratoryaction consequently diminishes gradually toward the discharge end of thescreen, whereby the screen approaches a maximum efficiency.

It is to be understood that the word spring may mean any yielding memberand therefore I do'not desire to limit my invention to the precise termsor details of construction and arrangement as herein set forth as it isobvious that various modifications may be made therein without deparfling from the essential features of my invention as defined in theappended claims.

Having thus described my invention, I claim 1. A device of the classdescribed comprising a spring support, ascreen mounted thereon andcapable of longitudinal adjustment with respect thereto, means forvibrating the support, and means for suspending the support in suchinamier that when the support is vibrated th vibratory impulsesthroughout the support will vary in amplitude.

2. A device of the class described comprising a spring support, meansfor suspending the support at its ends so that when vibrated thevibratory impulses will vary throughout its length and have a maximumamplitude of vibration equidistant from said points of suspension, meansfor vibrating the support, a screen, and means carried by the screen andadjustable longitudinally of the support for mounting the screen atspaced points upon the support.

3. A device of the class described comprising a spring having spacedpoints of suspension, means arranged to vibrate said spring, arscreenand means for supporting the screen on the spring, adjustablelongitudinally thereof and having spaced points of contact therewithwhereby the impulses of vibration throughout the length of said screenmay be varied.

4t. A device of the class described comprising a spring having spacedpoints of suspension, means arranged to effect the vibration of saidspring, and a screen carried by said spring and restricted thereby to avibratory motion in a direction normal to the plane ofthe screen surfaceand having spaced points of contact with said spring at relativelydifferent distances from the respective points of suspension of saidspring.

5. A device of the class described comprising a spring having spacedpoints of suspension, a vibrator carried by said spring arranged toeffect vibratory impulses thereof, a screen carried by said spring andhaving longitudinally spaced points of contact therewith, and meanswhereby said screen may be adjustedlongitudinally of said spring andsecured thereto with its points of contact at relatively differentdistances from the respective points of suspension. of said spring.

A 6. A device of the class described comprising a spring having spacedpoints of suspension, means arranged to effect vibration of said spring,a screen carried by said spring and having spaced points of contacttherewith and adjustable thereon to vary the relative distances betweensaid points of contact and the points of suspension whereby the impulsesof vibration of said screen may be varied, and means effective torelieve the weight of said screen from said spring.

7. A device of the class described comprising a screen, a longitudinallyextending resilient support therefor disposed substantially parallelthereto, having spaced points of suspension and operative to restrictthe screen to a vibratory motion normal to the plane of the screensurface, means arranged to effect vibration of said support, and anauxiliary spring tending to uplift said support and therebycounter-balance the weight of the screen.

8. A device of the class described comprising a yielding support havingspaced points of suspension, an out-of-balance wheel carried by thesupport and arranged when actuated to effect vibration of said supportintermediate of its points of sus pension, whereby the region of maximumamplitude of vibration is normally equidistant from said points ofsuspension, and a screen carried by said yielding sup port and havingspaced points of contact therewith and adjustable thereon to vary therelative distances between said points of contact and the points ofsuspension whereby the region of maximum amplitude of vibration of saidyielding support is shifted and the impulses of vibration of the screenso varied that said impulses gradually diminish throughout the length ofsaid screen.

9. In a screening device, the combination with a yielding support havinglongitudinal slots, of relatively spaced mountings for said supportpermitting its free vibration, means arranged to effect vibration ofsaid support, a screen having relatively spaced standards engaged withsaid sup port and arranged for longitudinal adjustment along saidsupport, and means cooperative with said standards and said slotsarranged to adjustably secure the screen and support together indifferent longitudinal relation.

10. In a screening device, the combination with a spring having spacedpoints of suspension, :of means arranged to effect vibration of saidspring, a screen hav ing a frame carried by said spring and havingspaced points of contact therewith, a pan carried by the screen frameand extending substantially parallel with said screen in spaced relationthereto, and means independent of said frame arranged to connect saidscreen and pan to insure their vibration in unison.

11.-In a screening device, the colnbinal'aininous diaphragm With saidtransverse tion With a screen frame comprising side bars intermediate ofsaid side bars, and bars, of means arranged to effect the vi'braspacingsleeves through Which said bolts tion of said fralne a foraininousdiaextend arranged to space said foraniinous phragn havingitsinarginsengaged with said diaphragm and said pan and to insureside bars, aniznperiorate pan subjacent to their vibration in unison. I

said fera-n'iinous diaphragin a plurality of In Witness Where -i, I havehel eunte set transverse bars connecting said side bars my hand this lthday of August, 1924.

and underlying said pan, bolts extended through said pan and connectingsaid to- CHARLES 'E. BARHIGHT.

